I. Introduction
Due to the explosively increasing demand for mobile data and high data rates, tremendous requirement for energy is raised for both the transmitters and the receivers in order to guarantee the quality of service (QoS) for users. The concept of simultaneous wireless information and power transfer (SWIPT) has been introduced in wireless communication systems to enable energy self-sustainability for the battery limited portable devices. Various researches have been conducted with respect to SWIPT. In [1], the authors investigate a three-node robust SWIPT with multiple-input, single-output (MISO) configuration. The authors in [2] extend the previous work to multiuser scenarios with the assumption of perfect channel state information (CSI).